Dynamo-electric machine



(No Model.) 4 Sheet-s8heet 1. O. M. GREEN. DYNAMO ELECTRIC MACHINE.

Patented Aug. 3,1897.

(No Model.) 4 Sheets Sheet 2 C. M. GREEN. DYNAMO ELECTRIC MACHINE.

No. 587,576. Patented Aug. 3,1897.

(No Model.) 4 Sheets-Sheet 3. G. M. GREEN.

DYNAMO ELECTRIC MACHINE.

No. 587,576. Patented Aug. 3 1897.

Y C. M. GREEN. DYNAMO ELECTRIC MACHINE.

4 Sheets Sheet 4.

(No Model.)

Patented Aug. 3,1897. I

UNITED STATES PATENT Orricn.

CHARLES M. GREEN, OF CLEVELAND, OHIO.

DYNAMO-ELECTRIC MACHINE.

SPECIFICATION forming part of Letters Patent N 0. 587,576, dated August3, 1897.

Application filed November 10, 1896. Serial No. 611,663. (No model.)

T 0 all whom it may concern/.-

Be it known that 1, CHARLES M. GREEN, of Cleveland, in the county ofOuyahoga and State of Ohio, have invented certain new and usefulImprovements in Dynamos; and I do hereby declare the following to be afull, clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame.

My invention relates to an improvement in dynamo-electric machines, andrelates to an improvement in the armature and commutator connections fora multipolar machine.

In the operation of multipolar machines it has been found that wheneveran attempt is made to push up the voltage much above the normal outputof such machines di lliculty has been experienced in ell'ectin gsatisfactory commutation. In building multipolar machines of a greatercapacity than any which have been built up to the present time,onehundred-and-twenty-live-light arc-machines being the largest thathave thus far gone into commercial use,it is desirable that such largermachines be rendered more stable than the one hundred andtwenty-five-light arc-machines now in use, since flashing on a ma chinehaving a capacity of operating three hundred and sixty or more arc-lampswould be attended by much more serious conse quences than on a machineoperating only one hundred and twenty -five lamps. It has been foundthat two thousand volts is about the maximum voltage that can be safelycommutated on a single commutator ring employed with open-coilarc-machines, and in order to keep within this prescribed limit of notover two thousand volts on each commutatonring of athree-hundredand-sixty-arc-light machine nine con1mutator-rin gs wouldbe required under the present method of commutation. Such a commutatorwould be so long and cumbersome as would render it most undesirable.

The objects of my invention are to so con struct an armature andcomn'iutating device that the aggregate output of the armature coilswill be distributed among several sets of commutatorbrushes, to reducethe num ber of commutatonrings to a minimum for a multipolar machinehaving an armature OOD1 prising a large number of bobbins, and .to

employ more than two brush-studs around the commutator.

lVith these objects in view the invention consists in certain novelfeatures of-eonstruction and combinations and arrangements of parts, aswill be hereinafter set forth, and pointed out in the claims.

In the accompanying drawings, Figure 1 is a diagrammatical viewillustrating one embodiment of my invention. Fig. 2 is a view showingthe groups of armature bobbins cross-connected. Fig. 3 is a diagramshowing a method of reducing potential. Fig. 4 is a view'showing thesets of armature-bobbins and field-coils connected in parallel with eachother. Fig. 5 is an enlarged detail view of a portion of the machine.

I have illustrated my invention as applied to an eight-pole dynamohaving an armature with thirty-two bobbins, the ends of the variousbobbins being connected with commu tater-segments located directly inline with said bobbins and the brush-studs and brushes disposedpractically at right angles to the various pole-pieces, so that the endsof a bobbin or bobbins generating current at a given time are connectedwith brushes and studs opposite one pole of the field-magnets instead ofwith opposite brushes or studs, as in some bipolar machines. The brushesare rocked forward as the load in the working circuit is .de creased, aspracticed in arcmachines of today.

In the drawings I have designated the fieldmagnets poles N as northpoles and S as south poles, there being eight poles, four north and foursouth, which alternate with each other as usual in a multipolar machine.

For sake of convenience in explaining my improvements the armature-coilswill be divided into eight sets of four bobbins each and are designatedA '3 C D A &c., and so on, ending with D Each commutator-ring comprisestwo annular series of segments spaced apart, the. segments of one setalternating with thoseof I the other set. These commutator-rings arecommutator brushes are employed, four brushes being carried by eachstud, and are indicated by a b c d &c., to

In tracing the circuit through the armature we may for convenience startwith the plus brush A, which in the drawings is shown bearin on se mente of commntatorrin D D D Lil R, with which segment one end of the bobbinA is connected. From bobbin A the circuit may be traced to segment 6 ofcom mutator-ring R on which brush Z) bears, thence,

by conductor u to brush 0', which bears on segment 6 and i of ring Rthence from segment 6 of ring B through bobbin D to brush (1, whichbears on segment e and t of ring R, the circuit extending, therefore,also through bobbin 15 Thus bobbin A will be connected in series andbobbins D and B in parallel.

The brush (Z is connected by a conductor 01? with brush (Z of the nextset of brushes. The circuit can now be readily traced through thebobbins B and D in parallel and bobbin A in series, thence by conductorit to brush (t thence through bobbins A in series and B and D inparallel, thence by conductor a from brush (1 to brush (Z of the nextset, thence through B and D" in parallel and A in series, thence byconductor "U5 to brush a of the next set, thence through bobbins A inseries and DD in parallel, thence by conductor it to brush (Z6 of thenext series, thence through bobbins B and D in parallel and A in series,thence by conductor a to brush (L7 of the next set, and thence throughbobbins A in series and B and D in parallel, thence by conductor lb tobrush (Z of the next set, thence through bobbins B and D in parallel andA in series and to minus brush a Thus it will be seen that two of eachset of tour armature-bobbins will be connected in parallel, one bobbinof each set will be connected in series, and the remaining bobbin ofeach set will be cut out, the ends of the fourth bobbin being connectedwith commutatorsegments on which no brush bears for the time being. Viththe armature in the position shown in the drawings and the circuitsarranged for the time being in the manner above explained the bobbins C,0 C 0', C, 0, C and C are in the weakest part of the iield andopen-circuited.

From the above it will be observed that the current generated in thevarious sets of coils or bobbins will be commutated simultaneously by acorresponding number of sets of commutator-brushes and that the varioussets of brushes are in effect connecl ed in series with each other.

By my improvements Iain enabled to take off currents of high voltagefrom a large multipolar dynamo capable of operating three hundred andsixty arc-lamps without employing a large number of com mutator-ringswith only two brush-studs. I am also enabled to and in practice woulddivide the output of the machine and utilize the current generated inseveral lamp-circuits, thereby reducing the difference of potentialbetween dil't'erent parts of the machine and circuits. For instance, theconductors 14 14 n can be extended, as shown in Fig. 3, to form severalexternal circuits, in which lamps or other translatii'ig devices may beincluded. The conductors it it to u might also be extended or drawn outto constitute external circuits. Thus several external circuits may betaken from the machine and all of said circuits be in series with eachother.

It has heretofore been proposed to independently commutate the currentgenerated in each pair of armature-coils in a bipolar machine and withan armature composed of a comparatively small number of coils, but itwould not be practical to adopt this method of commutation withamnltipolar machine employing an armature with a large number of coils,(thirty-two coils, for instance,) because a commutator of excessivelength would be necessary. By my improvements I am enabled to in effectindependently eominutatc the current generated in several series of thearmature-coils and produce results equal in efliciency to thoseaccomplished by using a commutator with a sufficient number of rings toindependently com mutate each pair of coils without the necessity foralong commutater.

By the construction and arrangement of the apparatus as above describedI am enabled to regulate the amperage of the machine by merely alteringthe relations of the sets of bobbins to each other. For instance, when alarge voltage and low amperage is desired the several sets of coilswould be connected in series, as above explained, but when it is desiredto raise the amperage the several sets of coils may be connected inparallel, as shown in Fig. 1, thereby doubling or quadrupling theamperage and reducing the vol tage in the same proportion. This canreadily be accomplished by changing the exterior connections on themachine and without disturbing any of the internal connections.

In the form of the invention shown in Fig. 2 only four sets ofcommutator-brushes are employed and each two groups of armaturebobbinsare cross-connected On account of the cross connection of the bobbinssome of the commutater-segments must also be crossconnected. It will beremembered that the ends of the bobbins in the form of the inventionshown in Fig. 1 are connected, respectively, with segments of twoadjacent commutator-rings and that there are eight sets of bobbins andeight sets of commutator-brushes. Now with the form of the inventionshown in Fig. 2, which shows the same number of bobbins as in Fig.1,there is just one-half the number of sets of commutator-brushes, and thegroups of bobbins are erossconnected, as above stated. Hence thecommutator-segm cuts with which one set or group of bobbins is connectedmust be cross-connected with the commutator-segments with which theadjacent set of bobbins is connected. Thus in Fig. 1 one end of bobbin Ais connected with a segment of commutator-ringR and the other end ofthis bobbin is connected with a segment of the adjacent com 111utator-rin g Rfiand comm utater-brushes bear on both of these segments,while in Fig. 2 the outside end of bobbin A is connected with a segmentof commutatorring R, and the inside end of said bobbin iscross-connected with the bobbin A The outside end of the bobbin A isconnected with another segment of the commutatorring R, but as no brushis 110w bearing on this segment the latter must be cross-connected withthe segment of riu g R with which the bobbin A would have been connectedhad it not been cross-connected with the bobbin A.

My improvements are comparatively simple in construction and effectualin all respects in the performance of their functions.

Slight changes in details might be resorted to without departing fromthe spirit of my invention or limiting its scope, and hence I do notwish to limit myself to the precise details herein set forth.

In this case I do not broadly claim a system of electric generation anddistribution consisting of generating electromotive force in two or moresets or groups of armaturecoils and distributing the electromotive forceso generated in separate external circuits and connected between andincluded in series with such separate groups of armatureconductors, suchinvention being covered, broadly, by claims in my pending applicationfiled April 18, 1896, Serial No. 588,108, and is reserved to beprotected by the patent granted thereon.

Having t ull y described my invention, what I claim as new, and desireto secure by Letters Patent, is

1. In a multipolar dynamomachine, the combination with a series of commutatorrings, of armature-coils connected with commutator-segments at thesame side of the ar mature fi f'f f'lcll the coils are located, andseveral sets of commutater-brushes to engage said commutator-rings.

2. In a multipolar dynamo-machine, the combination with an armaturecomprising several sets o'fcoils, of a commutator consisting of severalsegmental rings, and several sets of commutator-brushes, the brushes ofeach set being located on the same side of the commutator and arrangedalternately positive and negative, substantially as set forth.

3. In a multipolar dynamo-machine, the combination with an armature anda commutator comprising several segmental commutator-rings and sevcralsets of commutator: brushes, the brushes of each set being alternatelypositive and negative and the intermediate positive and negative brushesof each set being electrically connected together,sub- Stantially as setforth.

4. In a multipolar dynamounachine, the combination with an open-coilarmature comprising several sets of coils, of several segmentalcommutator-rings,several sets of commutator-brushes and externalcircuits between each two sets of brushes.

5. In a multipolar dynamo-machine, the combination with segment-a1commutatorrings, of armature-coils, each coil having its respective endsconnected with segments of two rings, said segments being in line witheach other and with the coil connected to them.

6. The combination with an armature having several sets of coils, of aseries of commutator-rings, each ring comprising two series of segments,the segments of one series alter nating with those of the otherseries,the segments of one ring being in line with the segments of another ringand several sets of comnmtator-brushes, the brushes of each setcorresponding in number to the number of commutator-rings and each brushadapted to engage both series of segments of the respective rings, theseveral sets of brushes being connected in series with each other,substantially as set forth.

7. In a multipolar dynamo machine the combination with an open-coilarmature comprising several sets of bobbins, of a commutator comprisingseveral segmental rings, several sets of brushes to bear on said rings,said bobbins, commutator rings and brushes being so arranged that onebobbin of each set will be connected in series, two bobbins of each setin parallel and the remaining bobbin of each set out out, the severalsets of brushes being connected in series and translating devicesbetween the sets of brushes, substantially as set forth.

8. In a dynamo-electric machine, the combination with a multiplicity offield-magnet poles, of an armature having several times as many bobbinsas there are field-magnet poles, a series of segmental commutator-ringsequal to the total number of bobbins divided by the number offield-magnet poles, sets of brushes corresponding in number to thefieldmagnet poles, the brushes of each set corresponding to the numberof commutator-rings and the various sets of brushes being connectedtogether in series, substantially as set;

bination with a series of field-magnet poles and several segmentalcommutator-rings, of an armature having several sets of bobbins, bothends of the various bobbins being connected to commutator-segments inline with them, on the same side of the commutator, and several sets ofbrushes bearing against said commutator-rings, substantially as setforth.

10. In a multipolar machine, the combination with a commutatorconsisting of aseries of rings, each ring being composed of two sets ofsegments arranged side by side, the se ments of one set alternating withthe segments of the other set, and armaturebobbins,

the opposite terminals of which are connected 1?. The combination with amultipolar ma chine havinp' several commutator-rings, a correspondingnumber of sets of commutatorbrushes, and flllllfttlll'OdJObblllS havingtheir opposite terminals connected to the same side of the commutator,of several circuits, each of which is interposed between thecoininuta-tor-rings, substantially as set forth.

In testimony whereof I have signed this specification in the presence oftwo subscribingwitnesses.

CllARLES M. GREEK.

\Vitnesses:

S. M. IIAMILL, C. J. L'EEPHART.

